Beyerdynamic X Astell&Kern T9iE Review

Beyerdynamic X Astell&Kern T9iE Review

Written by Chrono


The T9iE is the third in-ear headphone born from the collaborative efforts of Beyerdynamic and Astell&Kern, and it retails for $1299. The aim of the AK T9iE is to deliver an uncompromised, enjoyable, and faithful listening experience regardless of where you go, and to this end, it refines upon the Tesla-magnet-driven design of the T8iE MKII.

So, with this new implementation of Beyerdynamic’s Tesla technology, does the T9iE deliver? Let’s find out!

Sources and Music Used in Listening Tests

All the listening for this review was done on the Astell & Kern SR25 , and the Astell & Kern Kann Alpha . For the listening tests I used music from a wide variety of genres including Rock, Jazz, Classical, Acoustic, Hip-Hop, and latin. I played tracks from my own FLAC library, as well as from Qobuz and Tidal via Roon when using the Kann Alpha in DAC mode.

Astell&Kern T9iE Review |


Packed alongside the T9iE is a rather fine suite of accessories. For starters there are ten sets of ear tips included, seven sets of Beyerdynamic silicone ear tips (XS-XXL), and three sets of Comply Sports Pro Memory Foam tips. Additionally, there is a black leather Beyerdynamic + Astell&Kern hardshell case with a magnetic flip-up liod. The case looks protective, and feels nice, though unfortunately it’s quite bulky and definitely not pocketable; though, of course, it’ll easily fit into most bags when on-the-go. Last but not least there is the included cable, which thanks to feeling remarkably premium and tangle-free, is by far my favorite stock cable of any IEM I‘ve tried. It’s a 4N Pure SIlver and 7N OCC Copper hybrid cable featuring MMCX connectors for the ear-piece side, and a 2.5mm 4-pole balanced connector with a 3.5mm adapter on the source end.

Build and Comfort

As expected from a Beyerdynamic product, the build on the T9iE is rugged and flawless from what I can tell. The chassis is composed entirely out of metal, and is hand-assembled in
Germany. Unfortunately I don’t have much to say here, the design and build is second-to-none, and I doubt these will exhibit issues even after years of listening.

On the other hand, comfort was a bit mixed for me. I’d describe the T9iE as being a small to medium sized IEM, however its contouring and shape wasn’t one that I personally found to be particularly ergonomic. If I didn’t fit the IEM on perfectly and adjusted it while wearing it, it tended to put pressure on my ears, which would quickly result in fatigue and it even left my ears slightly sore after listening sessions. Now, I should mention that this was only an issue with the Beyerdynamic tips, which set the IEM deeper into the ear canal and I had no issues with the foam tips, which were actually pretty comfortable. Nonetheless, I think that this will vary greatly between users and will be heavily dependent on ear shape--so, mileage will vary.

Astell&Kern T9iE Review |


Honestly, I wasn’t sure what to expect from the T9iE. Before trying these out, my only experiences with Beyerdynamic had come from over ear headphones, and for the most part I labeled those ventures as “hot treble.” However, that was not the case at all with T9iE…

First Impressions

When I first listened to the T9iE I was shook. Its tonality couldn’t possibly be any further from the sound signature I typically associate with Beyerdynamic headphones. Unlike--for example--a DT 770 Pro, it’s not V-shaped, and instead it does have a more neutral-leaning balance to it that isn’t overwhelming in any one frequency range. Additionally, the T9iE is perhaps the most relaxed and warm-sounding IEM I’ve listened to; it had an easy-going and enjoyable presentation. This is not to say that it wasn’t without its issues, however. Since, as we’ll discuss briefly, the T9iE does have a few timbral quirks here and there.


The T9iE has a full, and present bass response. Its bass shelf is perhaps set a couple of decibels north of what would be considered “neutral,” but it’s not overdone, and I feel as though this really helps the T9iE in reproducing low frequencies with depth and more defined rumble. One thing I noticed, though, was that T9iE’s bass shelf doesn’t settle early enough. This resulted in the upper-bass having a little of extra bloom to it, and it also bled slightly into the lower mids. For the most part, this didn’t really make the bass response lose its cleanliness, nor did it make it less enjoyable for me, but it did detract from its precision. Overall, this is subtle, but if you’re looking for a reference headphone and what the highest degree of accuracy, this is worth keeping in mind.


The midrange on the T9iE is fairly interesting as I do think that, generally, it does have what I would consider to be a good tuning. Despite having the kind of sound signature that it does, the upper midrange in the T9iE has very good presence and doesn’t have the usual 2.5-4.5Khz dip that warm headphones tend to have. The only thing that stood out to me was that because of the upper bass bleed I mentioned previously, fundamental tones in the lower mids were emphasized. This is not unlike the tonal-enriching 200-350hz bump in the HD650, though it is more pronounced on the T9iE and it can occasionally make things like vocals teeter on the line of coming through as a bit congested. Aside from that though, I found the mids to be pretty well-tuned; past 400hz they did even out, and were linear throughout. Overall, midtones were portrayed adequately, though I will note that for listeners sensitive to slight timbral changes, the accented lower mids might slightly throw you off.


If there’s one thing that has never ceased to be a point of controversy in my past experiences, it’s the treble range on Beyerdynamic headphones. However, that is not the case with the T9iE, as it’s actually got a mostly-even, and laid-back treble range.

Admittedly it’s a touch too warm for my personal preference--particularly at around 9Khz and onwards--but I strongly believe that this might just be the best treble tuning I’ve heard in a Beyerdynamic headphone. To me, it did seem to have a slight peak at around 5.5Khz, but it was subtle and it only introduced some lower treble glare. Again, I do think that it could have used a bit more energy in the upper treble just to fully flesh out and nuance the harmonics in that region, but I think that if you enjoy warmer upper registers like that of the HD650, then you’re likely to find the T9iE to be quite pleasing in this regard--definitely friendly for those who are treble adverse.

Astell&Kern T9iE Review |


I’m not gonna lie, when it came to the T9iE’s overall sense of image clarity and detail retrieval, I was a tiny bit disappointed. That isn’t to say that it doesn’t perform well, as it does actually deliver a clean and cohesive image of the music. However, for an IEM that retails for $1299, I was expecting a more significant leap in internal resolution when compared to the Moondrop A8 , for example. Still, in isolation, it does achieve a high-level of image transparency and it accurately textures all instrument and vocal tones.

Soundstage, Imaging, and Layering

I personally found the soundstage presentation to be excellent on the T9iE. As with most IEMs it’s still a more forward, and intimate soundstage, but it does manage to feel spacious. It’s got outstanding layering, which properly spaces out different tracks in a mix, keeping them all distinct, and it’s also got fairly precise left-right localization with no gaps that break the soundscape.


The T9iE is utilizing a dynamic driver, so unsurprisingly, it creates a very good sense of punch and slam. Low tones are well-defined, with a satisfying impact and kick behind them. Additionally, the T9iE feels tactile and is adept at reproducing the gentle attack of things like piano keystrokes and guitar strings being plucked. Without a doubt, the T9iE is an energetic IEM in this regard, and it keeps the listening experience highly engaging.


Besides the comfort changes that the Sports Pro Foam tips from Comply provide, there was a pretty noticeable change in the T9iE’s tuning when rolling between them and Beyerdynamic’s tips. I would say that, at least in my experience, going with the foam tips pushed the T9iE towards having a more “neutral” frequency response. The bass shelf was slightly toned down, the lower mid bump was seemingly gone, and the treble did become just a little bit more pronounced. I think that the inclusion of the foam tips is great since it adds a bit of versatility without the need for EQ, and it provides a more reference tuning for the T9iE. The one thing I will mention, though, is that the 5.5Khz peak did become more pronounced with the foam tips and began to introduce a bit of sibilance in the lower treble.


So this is a first for an IEM review from me… Let’s try some EQ!

Ok, so usually I’m not too interested in EQ when using IEM’s because using a parametric equalizer on-the-go or with DAP’s isn’t really the easiest thing to do, and therefore I strongly believe that the stock FR is a lot more significant than it is on over-ear headphones. However, for those who do like to play around with EQ on IEM’s, I thought I’d share the settings that I personally enjoyed best when listening to the T9iE. If you’d like to try my EQ preset out, these were the settings I used (with Beyerdynamic eartips)

  • Peak at 250hz, -2dB Q of 2
  • Peak at 5500hz, -3.5dB Q of 3
  • High Shelf at 9000hz, +2dB Q of 0.7

Astell&Kern T9iE Review |


All in all, I really enjoyed my time with the T9iE. Compared to other IEM’s I’ve tried, it’s unique in that it goes for such a relaxed and warm tuning whilst also providing a good balance and technical performance. Despite it being a well-rounded IEM, though, it’s lack of price competitiveness makes me struggle to recommend it. When taken into the context of the current IEM market, it’s very tough to justify the T9iE’s purchase at its whopping $1299 price tag. For the additional $600 it demands over something like the Moondrop A8, I think it fails to really offer anything special in return.

If the T9iE goes on-sale for around $900, then I do think that it’s worth a look, particularly if warmer frequency responses are what you enjoy the most. However, whilst it’s not on-sale, I would personally save my money and look for an alternative, as there are many options in the market that achieve similar acoustic performance at a much lower price.



Buy the Astell&Kern T9iE for the best available price.


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